BP Flashcards
3 anti fungal drugs and their targets
Azoles - block alpha 14 demethylase (a fungal cytochrome P450) = formation of ergosterol = increased cell wall permeability, inhibition of replication
Polyenes - bind to sterols in the membrane, bind to ergosterol with higher affinity - forms ion channel = loss of rigidity
Mitotic inhibitors = inhibit cell division by interfering with spindle formation
3 main administration methods for anti-fungals
Oral
IV
Topical
Calculate clearance
Cl = Vd x Ke
Dose/AUC
Ke
Elimination constant
0.693/half life
Vd
Volume of distribution
Drug in body/drug in plasma conc
Why is clauvanic acid commonly prescribed with beat lactic antibiotics?
Inhibits beta lactamases which break down beta lactic antibiotics
Graded Vs Quantal curves
Graded looks at the response of an individual with increased concentration
Quantal looks at a specific response of a population with an increased concentration
Graded = sigmoidal
Quantal = n
What 2 drugs increase likelihood of candidiasis infection?
Glucocorticosteroids
Immunosuppressants
What type of drug is morphine?
What is it used to treat?
Opioid
Moderate to severe pain, terminal care
What type of drug is codeine?
What is it used to treat?
Side effects?
Weak opioid
Mild to moderate pain, cough suppression, antidiarrhoeal
Constipation
Where do benzodiazepine accumulate, why?
Side effects
Mechanism of action
Body fat because they have a high lipid solubility
Long lasting hangover, amnesia, sexual fantasies, dependency
Binds to specific regulatory site on the GABAa receptor - increasing the affinity for GABAa molecule = increased frequency of binding = increased inhibition of neuronal signals to brain = treat anxiety
How do benzodiazepines differ from barbiturates?
Barbituates increase the binding duration of GABA, benzodiazepines increase the frequency of binding
2 ways of sedating a patient other than benzodiazepine?
Inhalation of nitric acid
H1 antagonist
What does heparin bind to? mechanism of action?
What is a better version of heparin, why?
Antithrombin
Binds to antithrombin III which accelerates the inhibition of thrombin and clotting factors
Low molecular weight heparins have more constant activity because they only bind antithrombin III
How is heparin administered? why?
IV or SC
Not absorbed from the gut (high PPB)
Method of warfarin administration?
Oral
Mechanism of action of warfarin?
Inhibits hepatic synthesis of vit K dependent clothing factors by inhibiting vit K reductase
Speed of action for warfarin?
1-2 days
What does aspirin cause?
NSAID = anti platelet, antipyretic, analgesic, anti-inflammtory
How does aspirin have an antiplatelet action?
Inhibits eiconsaoid production by inhibiting COX
Inhibits COX mediated release of TXA2 and PGI2
TXA2 = promotes aggregation
PGI2 = inhibits aggregation
PGI2 is endothelium derived so makes more
TGA2 is platelet derived so no more made
= reduce platelet aggregation
How do antidepressants work?
TCA’s inhibit 5-HT and NA reuptake but this isn’t selective to also blocks M1 H1 and alpha 1
SSRI are selective
Monamine oxidase inhibitors = block the breakdown of Na to amines
More NA or 5HT in neurotransmitter in synapse
How do antidepressants cause dry mouth?
TCA are not selective block M1 receptors = block parasympathetic effects = decreased saliva flow = dry mouth
Mechanism of action of LA?
Block electrical signalling in neurones by blocking Na+ channels
How to calculate half life?
From graph or 0.693/Ke
2 pregnancy hormones related from anterior pituitary gland and function of each?
FSH = development of follicle LH = caused progesterone release from ovaries
2 pregnancy hormones related from ovary? function?
Progesterone - renders endometrium dutiable fro implantation, inhibits FSH and LH
Oestrogen - proliferation of endometrium, inhibits FSH
Metabolism of NA
Re-uptake transporter transports it back into pre-synaptic vesicle where it is metabolised to amines by MAO
Metabolism of ACh
By acetylcholinesterase in the synapse
What effects rate of distribution?
Membrane permeability and blood perfusion
What effects extent of distribution?
Lipid solubility, pH-Pka, tissue binding, PPB
Competitive orthosteric antagonist?
Binds reversibly to the active site (same site as drug)
Prevents agonist action but can be overcome with increased agonist concentration
Concentration response curve of competitive orthosteric antagonist?
Parallel but shifted to the right
What does a partial agonist appear like?
Maximum response falls short to the maximal response a system is capable of
What is aciclovir best against?
Herpes simplex virus
How is aciclovir selective?
Needs to be phosphorylated to be effective, so utilise simplex specific kinase for monophsophorylation